Active control method for passing through critical speeds of rotating shafts by changing stiffnesses of the supports with use of memory metals

Abstract

This paper describes a method of active vibration control for passing through critical speeds of a rotating shaft by use of support springs made of memory metals. In this method the vibration of the shaft due to whirling is controlled by means of on (heating) and off (cooling) heat control of memory metals for bearing supports. In the analysis the exact solution for whirling problems of a multi-stepped and multi-span shaft carrying a disk which is controlled by this method is derived. Numerical calculations have been carried out for some important problems and experimental tests also have been carried out to verify the present control method and the theoretical results.